The present invention relates to power tools and, more particularly, to adjustable workpiece supporting tables used in combination/multipurpose woodworking tools.
A multipurpose woodworking tool consists of a frame, an electric motor mounted in a headstock on the frame and having an output shaft to which is attached a tool member such as a saw blade, and a main table having a substantially planar surface for supporting a workpiece. The main table typically is mounted on the frame and is adjustable so that the supporting surface can be pivoted relative to the horizontal. The saw blade or other tool member extends upwardly through a slot in the main table, so that a workpiece may be slid across the supporting surface to engage the tool member.
In order to provide a capability of performing bevel cuts, the saw table typically is pivotable at least 45.degree. toward and away from the headstock. Consequently, the table must be made sufficiently narrow to be tilted without contacting the frame supporting the table.
With some multipurpose tools, the headstock and table are adjustably mounted on a pair of rails or tubes which can be tilted from a horizontal position to a vertical one, so that the motor is above the table with the output shaft extending downwardly to it. In this configuration, the multipurpose tool functions as a drill press. However, to provide a supporting surface for the drill press, the table must be tilted 90.degree. so that it is perpendicular to the axis of the output shaft. To accomplish this, the main table typically is relatively narrow in width contacting the table support structure and preventing further tilting movement.
In order to provide a support for relatively long workpieces when the rails are in a horizontal position, woodworking tools having short main tables often include a secondary table, mounted on the frame a distance from the main table, for supporting the end of a workpiece. Such a device is disclosed in the Edgemond, Jr. et al. U.S. Pat. No. 2,927,612. That patent discloses a multipurpose woodworking tool having a support frame, a headstock which encloses an electric motor and is adjustably mounted on a pair of horizontal rails, a pivotable main table adjustably mounted on the rails and positioned adjacent the headstock, and a secondary table, mounted on an end of the frame.
Since the secondary table is fixed horizontally relative to the frame, the locations of the headstock and main table along the rails must be adjusted so that the distance from the main table to the secondary table is appropriate to support a particular workpiece. To support a large workpiece, time-consuming steps of repositioning both the headstock and main table on the horizontal rails may be required. Furthermore, should it be necessary to provide a secondary table on an opposite side of the main table, the secondary table must be removed from its support on one end of the frame and reattached to the opposite end of the frame.
An alternate apparatus is disclosed in the Edgemond, Jr. et al. U.S. Pat. No. 3,021,881. That patent discloses a power table saw in which the main table is integral with the frame that supports the motor and saw blade. A pair of rails are adjustably attached to opposite sides of the main table and support cross members which are adjustable in position relative to the rails and main table, so that a portion of a workpiece extending sidewardly from the main table is supported by a cross member. While this arrangement provides a measure of adjustability in terms of a workpiece supporting surface, it would be unacceptable for use with a pivoting table, since the relatively long rails would limit the degree to which the main table supporting them could be tilted from the horizontal.
The rails of that device are in the form of an open channel, and hence possess relatively weak beam strength. The cross members clamp to the rails along a relatively small portion of the rail length, so that the overall structure does not possess sufficient rigidity for supporting relatively massive workpieces or for providing support during difficult cutting operations.
Accordingly, there is a need for a workpiece support system which supports workpieces which are longer than the typical main table of a multipurpose woodworking tool, yet do not hinder the ability of the main table to be pivoted from the horizontal. Furthermore, such a system should be capable of providing an adjustable and rigid support for relatively massive workpieces or workpieces which are difficult to machine.